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GLOBAL BIOGEOCHEMICAL CYCLES, VOL. 22, GB1018, doi:10.1029/2006GB002854, 2008

Sediment organic carbon burial in agriculturally eutrophic impoundments over the last century

J. A. Downing

Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa, USA


J. J. Cole

Institute of Ecosystem Studies, Millbrook, New York, USA


J. J. Middelburg

Centre for Estuarine and Marine Ecology, Netherlands Institute of Ecology, Yerseke, Netherlands


R. G. Striegl

United States Geological Survey, Denver, Colorado, USA


C. M. Duarte

Institut Mediterrani d'Estudis Avançats (CSIC-UIB), Esporles, Spain


P. Kortelainen

Finnish Environment Institute, Helsinki, Finland


Y. T. Prairie

Département des Sciences biologiques, Université du Québec à Montréal, Montreal, Quebec, Canada


K. A. Laube

Laube Engineering LLC, Greeley, Colorado, USA


Abstract

We estimated organic carbon (OC) burial over the past century in 40 impoundments in one of the most intensively agricultural regions of the world. The volume of sediment deposited per unit time varied as a function of lake and watershed size, but smaller impoundments had greater deposition and accumulation rates per unit area. Annual water storage losses varied from 0.1–20% and were negatively correlated with impoundment size. Estimated sediment OC content was greatest in lakes with low ratios of watershed to impoundment area. Sediment OC burial rates were higher than those assumed for fertile impoundments by previous studies and were much higher than those measured in natural lakes. OC burial ranged from a high of 17,000 g C m−2 a−1 to a low of 148 g C m−2 a−1 and was significantly greater in small impoundments than large ones. The OC buried in these lakes originates in both autochthonous and allochthonous production. These analyses suggest that OC sequestration in moderate to large impoundments may be double the rate assumed in previous analyses. Extrapolation suggests that they may bury 4 times as much carbon (C) as the world's oceans. The world's farm ponds alone may bury more OC than the oceans and 33% as much as the world's rivers deliver to the sea.

Received 3 October 2006; accepted 14 September 2007; published 15 February 2008.

Keywords: agriculture; burial; impoundments; lakes; organic carbon; sequestration.

Index Terms: 0428 Biogeosciences: Carbon cycling (4806); 0458 Biogeosciences: Limnology (1845, 4239, 4942); 0496 Biogeosciences: Water quality; 1615 Global Change: Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912); 1815 Hydrology: Erosion.

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Citation: Downing, J. A., J. J. Cole, J. J. Middelburg, R. G. Striegl, C. M. Duarte, P. Kortelainen, Y. T. Prairie, and K. A. Laube (2008), Sediment organic carbon burial in agriculturally eutrophic impoundments over the last century, Global Biogeochem. Cycles, 22, GB1018, doi:10.1029/2006GB002854.